A multi-omics approach to identify factors involved in hair follicle growth and development
File(s)
Author(s)
Pantelireis, Nikolaos
Type
Thesis
Abstract
During hair follicle morphogenesis a condensation of dermal cells signal the overlying epithelium to induce formation of the hair follicle. This dermal condensation eventually forms the dermal papilla (DP), a small structure at the base of the adult hair follicle which controls differentiation patterns and hair cycle progression. Moreover, the DP, which is effectively a condensation of adult dermal cells, will induce new hair follicle morphogenesis after being excised from an adult hair follicle and re-implanted elsewhere in the skin.
When grown in 2D culture conditions DP cells lose their ability to induce new follicle growth. However, this capability can be restored by promoting 3D spheroid formation in DP cells through hanging drop culture. Meanwhile, papillary fibroblasts (PFI), which arise from the same progenitor as DP cells, are unable to induce new hair growth in either 2D or 3D cultures, signifying that DP cells hold intrinsic capabilities that become activated in spheroids, and affirming their importance in hair follicle induction.
Here, the hypothesis which states - specific changes occur in DP cells, but not PFI, when cultured in spheroids that restores an inductive mesenchymal niche – is tested. To understand the molecular changes underpinning this phenomenon, RNA-seq in combination with ATAC-seq was performed, enabling assessment of differential gene expression and associated changes in chromatin arrangement within the nucleus which can regulate gene expression. DP and PFI cells in both 2D and 3D culture conditions were sequenced, giving 4 conditions and allowing for the identification of both cell-specific and culture specific changes.
Several target transcription factors with potential regulatory roles in inductivity were selected with the aim of reprogramming non-inductive human 2D DP cells or PFI cells into an inductive state. Lastly, using an in vivo conditional knockout model the role of Mef2c on hair follicle cycling and morphogenesis was explored.
When grown in 2D culture conditions DP cells lose their ability to induce new follicle growth. However, this capability can be restored by promoting 3D spheroid formation in DP cells through hanging drop culture. Meanwhile, papillary fibroblasts (PFI), which arise from the same progenitor as DP cells, are unable to induce new hair growth in either 2D or 3D cultures, signifying that DP cells hold intrinsic capabilities that become activated in spheroids, and affirming their importance in hair follicle induction.
Here, the hypothesis which states - specific changes occur in DP cells, but not PFI, when cultured in spheroids that restores an inductive mesenchymal niche – is tested. To understand the molecular changes underpinning this phenomenon, RNA-seq in combination with ATAC-seq was performed, enabling assessment of differential gene expression and associated changes in chromatin arrangement within the nucleus which can regulate gene expression. DP and PFI cells in both 2D and 3D culture conditions were sequenced, giving 4 conditions and allowing for the identification of both cell-specific and culture specific changes.
Several target transcription factors with potential regulatory roles in inductivity were selected with the aim of reprogramming non-inductive human 2D DP cells or PFI cells into an inductive state. Lastly, using an in vivo conditional knockout model the role of Mef2c on hair follicle cycling and morphogenesis was explored.
Version
Open Access
Date Issued
2021-05
Date Awarded
2021-12
Copyright Statement
Creative Commons Attribution NonCommercial NoDerivatives Licence
Advisor
Higgins, Claire
Sponsor
British Skin Foundation
Singapore. Agency for Science, Technology and Research
Publisher Department
Bioengineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)